Impact of Current Transfer to Porous Stabilizer on Recovery Performance of Resistive-Type Superconducting Fault Current Limiters Using REBCO Tapes

Porous-stabilized rare-earth barium copper oxide (REBCO) tape is an effective structure to solve a trade-off between the current-limiting and recovery performances of the resistive-type superconducting fault current limiters (RSFCLs). In the present study, a current-transfer-type porous-stabilized REBCO tape was proposed to suppress hot spots on the tape, which caused a recovery delay. In this type of REBCO tape, two porous stabilizers with different roles are utilized. The boiling heat transfer performance is improved with one of the porous stabilizers fixed with insulating epoxy on the tape while the current is transferred to the other porous stabilizer to decrease the Joule heating in the hot spot. To design the structure of the current-transfer-type porous-stabilized REBCO tape, the heat transfer performance with a porous medium and insulating epoxy was evaluated. The results indicated that there were suitable specifications for the porous medium and insulating epoxy for high heat transfer performance. The recovery performance of the current-transfer-type porous-stabilized REBCO tape was evaluated with the prototype using the selected porous stabilizer and insulating epoxy. The experimental results showed that the tolerable Joule heating was dramatically improved via current transfer to the porous stabilizer owing to the suppression of the temperature rise of the hot spot. The recovery time was shortened to 0.8 s. The present study showed one way to suppress the hot spots with a simple structure while maintaining the high electrical resistance of the REBCO tape.